self.onmessage = function (e) {
  console.log("worker1", e.ports);
  if (e.data === "main") {
    const port = e.ports[0];
    port.postMessage(`worker1: Hi! I'm worker1`);
    port.onmessage = function (ev) {
      console.log("reveice: ", ev.data, ev.origin);
    };
  }
};
